U.S. patent number 8,976,539 [Application Number 13/427,520] was granted by the patent office on 2015-03-10 for optical transceiver having corrugated inner side surfaces.
This patent grant is currently assigned to Sumitomo Electric Industries, Ltd.. The grantee listed for this patent is Phillip J. Edwards, Nhan Huynh, Jignesh H. Shah, Lance R. Thompson. Invention is credited to Phillip J. Edwards, Nhan Huynh, Jignesh H. Shah, Lance R. Thompson.
United States Patent |
8,976,539 |
Edwards , et al. |
March 10, 2015 |
Optical transceiver having corrugated inner side surfaces
Abstract
An optical transceiver that reduces the EMI noise leaked
therefrom is disclosed. The optical transceiver provides a metal
housing, an optical subassembly, and an electronic circuit. The
metal housing includes a first space to install the electronic
circuit, and a second space to install the optical subassembly. At
least the first space has inner surfaces having a corrugated shape
to reduce the resonance of the electromagnetic waves.
Inventors: |
Edwards; Phillip J. (San Jose,
CA), Shah; Jignesh H. (San Jose, CA), Thompson; Lance
R. (San Jose, CA), Huynh; Nhan (San Jose, CA) |
Applicant: |
Name |
City |
State |
Country |
Type |
Edwards; Phillip J.
Shah; Jignesh H.
Thompson; Lance R.
Huynh; Nhan |
San Jose
San Jose
San Jose
San Jose |
CA
CA
CA
CA |
US
US
US
US |
|
|
Assignee: |
Sumitomo Electric Industries,
Ltd. (Osaka-shi, JP)
|
Family
ID: |
40997208 |
Appl.
No.: |
13/427,520 |
Filed: |
March 22, 2012 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20120177379 A1 |
Jul 12, 2012 |
|
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
12390179 |
Feb 20, 2009 |
8319118 |
|
|
|
61064225 |
Feb 22, 2008 |
|
|
|
|
Current U.S.
Class: |
361/800; 174/377;
361/816; 174/384; 174/350; 361/818; 174/385 |
Current CPC
Class: |
H05K
9/0058 (20130101); G02B 6/4292 (20130101); G02B
6/4246 (20130101) |
Current International
Class: |
H05K
9/00 (20060101) |
Field of
Search: |
;361/800,816,818
;174/50.5,350,363,366,377,382,384,385 ;398/135 ;277/920
;385/88,92,94 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
"Gigabit Small Form Factor Pluggable Module," XFP Promoters, Rev.
3.1, pp. 1-160, Apr. 2, 2003. cited by applicant.
|
Primary Examiner: Estrada; Angel R
Assistant Examiner: Cruz; Dimary Lopez
Attorney, Agent or Firm: Venable LLP Sartori; Michael A.
Aga; Tamatane J.
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATIONS
The present application is a continuation of U.S. application Ser.
No. 12/390,179 filed Feb. 20, 2008, which claims priority of U.S.
Provisional Patent Application No. 61/064,225 filed on Feb. 22,
2008; the entire contents of all of which applications are
incorporated herein by reference.
Claims
What is claimed is:
1. An optical transceiver operable in a transmission speed over 10
Gbps, comprising: a metal housing to enclose an electronic circuit
and an optical subassembly therein, the metal housing having inner
side surfaces with a plurality of corrugated shapes at least in a
portion to enclose the electronic circuit, wherein the inner side
surfaces include a first surface and a second surface extending in
substantially parallel to each other along a longitudinal direction
of the optical transceiver, and wherein the corrugated shapes fully
cover the first surface and the second surface.
2. The optical transceiver of claim 1, wherein the corrugated
shapes each has a pitch different from each other.
3. The optical transceiver of claim 2, wherein the first surface
includes the corrugated shape of a pitch of about 3.2 mm, and the
second surface includes another corrugated shape with a pitch of
about 2.9 mm.
4. The optical transceiver of claim 1, wherein the corrugated
shapes have a height of about 0.25 mm.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an optical transceiver, in
particular, the invention relates to an EMI shielding structure of
the optical transceiver.
2. Related Background Arts
The U.S. Pat. No. 7,195,403, has disclosed an arrangement of the
interconnection from the connector plug exposed in the external of
the optical transceiver to the electronic circuit set within the
transceiver. In this arrangement, the interconnection is buried
within the substrate, while the top and the back surfaces of the
substrate provide the ground patterns each coming in contact with
the shield gasket, which is made of electrically conductive elastic
material, to shield the electronic circuit in the transceiver from
the external.
Another U.S. Pat. No. 7,425,135, has disclosed a mechanism to fix
the flexible printed circuit board with the substrate. The flexible
printed circuit board electrically connects the optical
sub-assembly, such as transmitter optical sub-assembly or receiver
optical sub-assembly, with the electronic circuit prepared on the
substrate. Further, the multi-source agreement, titled "10 Gigabit
Small Form Factor Pluggable Module Rev. 3.1 (Apr. 2, 2003)" defines
the specifications of one type of pluggable optical transceivers
known as XFP transceiver.
As the transmission speed of the optical communication increases,
some standard comes up to 10 Gbps and over 10 Gbps is practically
designed, the electro-magnetic interference (EMI) noise leaked from
the equipment becomes an important subject. As a characteristic
wavelength becomes shorter, even a slight gap in the equipment,
which conventionally causes no effect for the EMI leakage, results
in a large EMI noise with high frequency components. The U.S. Pat.
No. 7,195,403 above described has disclosed an effective mechanism
to shield between the primary electronic unit within the optical
transceiver and the connector plug exposed externally. However, it
is inevitable for the optical transceiver to provide an optical
path in a side where the optical connector is mated that opens the
primary electronic unit to the outside. Thus, it is necessary for
the optical transceiver capable of transmitting high-frequency
signals to provide some shielding mechanism for the high frequency
EMI noise in the side of the optical connector.
Moreover, in such equipment that processes the high frequency
signals, a resonance frequency, which is roughly determined by the
physical dimensions of the space where the electronic circuit is
primarily installed therein, may partially overlap with the
operational frequency of the optical transceiver. This overlapping
of the resonance frequency with the operational frequency degrades
the frequency characteristic of the transceiver. As the frequency
spectrum of the resonance becomes sharp, the degradation in the
frequency characteristic of the transceiver is apparent.
One type of the optical transceiver is used in the host system such
that the transceiver is inserted into the cage prepared in the host
system to mate the connector plug provided in the rear end of the
transceiver with the connector installed in the deep end of the
cage, which secures the communication between the transceiver and
the host system. Such an optical transceiver is called as the
pluggable transceiver. Because the transceiver is inserted into the
cage, the outer dimensions thereof are regulated in a type of a
multi-source agreement (MSA). Therefore, it is practically
impossible to adjust the dimensions of the transceiver to escape
from the overlapping of the resonance frequency with the operating
frequency. It is necessary to shift the resonance frequency from
the operating frequency, or to moderate the frequency spectrum of
the resonance in the optical transceiver whose dimensions are
independently determined.
SUMMARY OF THE INVENTION
The present invention, which is to provide a solution for subjects
described above, has a feature to reduce the electro-magnetic
resonance within the metal housing. The optical transceiver
according to the present invention has a function for the host
system, where the optical transceiver is to be installed therein,
to convert an optical signal to an electrical signal mutually. The
transceiver comprises an electrically conductive upper housing, an
electrically conductive lower housing, an electronic circuit and an
optical subassembly. The upper and lower housings form, by
assembling with respect each other, a first space and a second
space. The first space installs the electronic circuit therein,
while, the second space installs the optical subassembly therein.
In the present invention, the first space and the second space are
electrically shielded each other in addition that both spaces are
shielded from an external.
The optical transceiver of the invention may further include a
circuit substrate to install the electronic circuit thereon. The
circuit substrate extends from the second space in an end thereof
to be connected with the optical subassembly to the external in
another end thereof to be mated with the host system through the
first space. The circuit substrate may provide a ground pattern at
a boundary around the first space.
In the optical transceiver according to an embodiment thereof, at
least the first space has inner surfaces with a corrugated shape to
reduce the resonance of the electromagnetic wave. The corrugated
shapes has various pitches to reduce the resonance further.
The present invention is better understood upon consideration of
the detailed description below and the accompanying drawings.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 illustrates an external appearance of the optical
transceiver according to the embodiment of the invention;
FIG. 2 is an exploded view of the optical transceiver shown in FIG.
1;
FIG. 3 illustrates an inside of the optical transceiver;
FIG. 4 illustrates a lower housing of the optical transceiver;
FIG. 5 illustrates an upper housing of the optical transceiver;
FIG. 6 is a cross section of the optical transceiver taken along
the longitudinal direction thereof; and
FIG. 7 magnifies a portion where the FPC board is connected with
the substrate; and
FIG. 8 is a side view of the FPC board with the substrate.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
FIG. 1 is an external appearance of an optical transceiver 10,
which is viewed from the bottom side thereof, according to an
embodiment of the present invention. The optical transceiver 10 is
a type of, what is called, an XFP transceiver whose outer
dimensions and electrical specifications are defined by a
multi-source agreement (MSA). The transceiver 10 has a housing with
the dimension of 18.3.times.71.1.times.8.5 mm.sup.3 and may perform
the optical communication with the full-duplex mode and of the
transmission speed of 10 Gbps. The transceiver 10 provides an
optical receptacle 11 to receive a duplex optical connector with
the LC-type in the front side thereof, while, it provides, in the
rear side, a plug connector 12 that is mated with an electrical
connector prepared in the host system that installs the optical
transceiver 10. Here, the front side corresponds to a side where
the optical connector is mated, while, the rear side corresponds to
a side where the electrical connector is mated. The transceiver 10
also provides an actuator 72 with a curled edge 72c in a tip end
thereof that releases the transceiver 10 from the cage on the host
system. The actuator 72 may slide in front and rear by rotating a
bail 71 in front of the optical receptacle 11. This sliding motion
of the actuator 72 may release the engagement of the transceiver 10
with the cage and may extract the transceiver 10 from the cage.
FIG. 2 is an exploded view of the transceiver 10 and FIG. 3
illustrates the inside of the transceiver 10 by removing the upper
housing 20. The latch-releasing mechanism 70 includes, as mentioned
above, the bail 71 and the actuator 72. These members, 71 and 72,
are assembled in the side of the optical receptacle 11. That is,
the bail 71 has a reversed U-shape with a pair of leg portions 71a
each providing a projection 71b in an inner side thereof. The leg
portion 71a further provides another projection 71c in a rear of
the first projection 71b. While, the actuator 72 has a normal
U-shape set between the leg portions 71a of the bail 71 so as to
fit the cross section of the bail 71. The sides 72d of the actuator
72 extend an arm portion 72b toward the rear side of the
transceiver 10. The end of the arm portion 72b provides the curled
edge 72c.
Inserting the first projection 71b of the bail 71 into the hole 31a
formed in the front side wall 31b of the lower housing 30, and
setting the second projection 71c in the arched groove 31c also
formed in the side wall 31b of the lower housing 30 by passing
through the arched slit 72e formed in the side 72d of the actuator
72, the latch-releasing mechanism 70 is assembled with the lower
housing 30. Rotating the bail 71 by the first projection 71b as an
axis so as to traverse the optical receptacle 11, it causes the
sliding motion of the second projection 71c in the arched groove
31c to slide the actuator 72 toward the front side of the
transceiver 10. Then, the curled edge 72c in the tip end of the arm
portion 72b pushes out the hook of the cage outwardly, which is not
illustrated in the figure, to release the engagement between the
transceiver 10 and the cage. Thus, the transceiver 10 may be
extracted from the cage.
The optical transceiver 10 roughly comprises the upper housing 20,
the lower housing 30, the substrate 40 that installs an electronic
circuit thereon, the receiver optical transmitter sub-assembly
(hereafter denoted as ROSA) 50, the transmitter optical
sub-assembly (hereafter denoted as TOSA) 60, and the
latch-releasing mechanism 70. The upper and lower housings, 20 and
30, both made of metal die-casting, are assembled to each other as
putting the gasket 80 therebetween to electrically shield the
circuit on the substrate 40 from the external. The gasket 80
comprises a first gasket 80a that shields a first space 10a where
the primary portion of the electronic circuit is installed therein,
and a second gasket 80b that shields a second space 10b where the
ROSA 50 and the TOSA 60 are installed therein. Assembling the upper
housing 20 with the lower housing 30, the optical receptacle 11 is
formed in the front side.
The substrate 40, which may be a multi-layered substrate, roughly
includes three portions. The first portion 40d installs the primary
circuit thereon, is set within the first space 10a and is shielded
with the gasket 80a. The second portion 40e includes a plurality of
pads connected with the FPC substrates, 91 and 92, each extended
from the ROSA 50 and the TOSA 60, and shielded with the second
gasket 80b. The third portion 40f includes the connector plug 12
and is exposed in the external. Interconnecting patterns, which
connect the connector plug 12 in the third portion 40f with the
primary circuit in the first portion 40d, run in the inner layer of
the multi-layered substrate 40; while, in the top and back surfaces
of the substrate 40 at the boundary between the first 40d and third
portions 40f provide the ground patterns 40g that comes in contact
with the gasket 80a. This ground pattern 40g in the top surface of
the substrate 40 extends into the first portion 40d so as to
surround the primary circuit in the first portion 40d. The ground
pattern 40g further extends in the boundary between the first 40d
and the second 40e portions of the substrate 40 and comes in
contact with the gasket 80a thereat again. Thus, the first space
10a may be fully shielded by gasket 80a, the ground pattern 40g and
the upper 20 and lower 30 housings.
A conventional optical transceiver often shields the electronic
circuit and the optical components as unifying the first space 10a
for the electronic circuit with the second space 10b for the
optical components. However, such an arrangement is hard to prevent
the leakage of the EMI noise thorough the optical path inevitably
existing between each sub-assembly, the ROSA 50 or the TOSA 60, and
the optical receptacle 11. The optical transceiver 10 according to
an embodiment of the present invention provides an additional
shielding mechanism in the boundary between the first space 10a for
the electronic circuit and the second space 10b for the optical
components; accordingly, even the EMI leakage through the optical
path is remained, the magnitude of the leakage may effectively
reduced.
In order to secure a heat dissipating path from the electronic
circuit, in particular, from the ICs 40a on the substrate 40 to the
outside, the heat sink 40b is put between the IC 40a and the upper
housing 20. The height of the heat sink 40b is adjusted so as to
fill a gap between the IC 40a and the upper housing 20. The top of
the side wall 30a of the lower housing 30 forms a step 30c with a
height of 0.75 mm. Setting the substrate 40 in a peripheral
portions thereof on this step 30c, and sandwiched by the upper and
the lower housings, 20 and 30, the substrate 40 is assembled with
the housings, 20 and 30. A plurality of screws 30e, three screws
are illustrated in the figure, fix the lower housing 30 to the
upper housing 20 as putting the substrate 40 therebetween. The
substrate 40 provides cut portion 40c to run off the rear screw
holes 30d in both sides thereof. Fitting this cut portion with the
wall of the screw holes 30d, the sliding motion of the substrate 40
in front and rear when the connector plug 12 is mated with the
connector on the host system may be prevented in addition that the
upper and the lower housings, 20 and 30, put the substrate 40
therebetween.
FIGS. 4 and 5 illustrate the lower housing 30 and the upper housing
20, respectively. The lower housing 30 provides the primary
structure of the optical receptacle 11 in the front end thereof.
Assembling the lower housing 30 with the upper housing 20, the
optical receptacle 11 with the specification of the LC-type
connector is formed. A portion in the rear of the optical
receptacle 11 forms the second space 10b for installing the ROSA 50
and the TOSA 60 so as to be surrounded with the side walls 31d and
the bottom 30i and the ceiling 20i. The second space 10b provides
saddle portions 30g whose shapes fit with the cylindrical outer
shape of the ROSA 50 and the TOSA 60. The ribs 30h perform the
optical alignment of the ROSA 50 and the TOSA 60, in particular,
the sleeve portions 50b and 60b thereof, with respect to the
optical receptacle 11. That is, a pair of flanges provided in the
sleeve portion, 50b and 60b, puts the rib 30h therebetween, which
determines the position of the OSAs, 50 and 60, along respective
optical axes. The upper housing 20 provides structures, 20g and
20h, similar to those prepared in the lower housing 30.
The first space 10a is partitioned from the second space 10b by the
walls, 21e and 31e, while, it is isolated from the external by the
walls, 21f and 31f, in the rear side of the transceiver 10. That
is, the first space 10a is surrounded by the side walls, 20c and
30c, in sides thereof, partition walls, 21e and 31e, in the front
while other partition walls, 21f and 31f, in the rear and the
bottom 30j and the ceiling 20j. Moreover, the first space 10a of
the present embodiment has a feature that the inner surfaces, 22a,
22b, 32a and 32b, of respective walls are formed in corrugated. The
height of the corrugation is about 0.25 mm in this embodiment,
while the pitch thereof is about 3.2 mm in the first sides, 22a and
32a, while, it is about 2.9 mm in the second sides, 22b and 32b,
which is different from the first sides.
The transmission speed of the optical communication has
continuously increased and it has come to 10 Gbps for the present
optical transceiver 10. When an electrical signal with such high
frequency components is processed within a closed space, the
resonance or the resonance frequency determined by the dimensions
of the closed space influences the frequency characteristic of the
circuit. The resonance frequency of the transceiver with the
dimensions of the XFP type according to the present embodiment
becomes a several giga-hertz to several tens of giga-hertz, which
just includes or overlaps with the transmission speed of the
transceiver 10. When the closed space is determined by the parallel
plate, the resonance determined by the inner distance between the
walls facing to each other becomes conspicuous and the high
frequency characteristic of the circuit within the closed space
degrades. The optical transceiver 10 according to the present
embodiment has the inner walls with the corrugated shape to
moderate the resonance. Moreover, the present transceiver may
further reduce the resonance above mentioned by setting the pitches
of the respective corrugation different from each other.
Although the upper and lower housings, 20 and 30, illustrated in
FIGS. 2 to 5 do not provide any groove to set the gaskets, 80a and
80b, therein in the top of the side walls, an arrangement where the
gaskets 80 in such a groove may facilitate the assembly of the
transceiver 10.
The second space 10b is formed by the partition walls, 21e and 31e,
in the rear end thereof, the saddle portions, 20g and 30g, in the
front side thereof, and a double structure of sloped walls, 21g and
31g, and outer walls 31d. Between the partition walls, 21e and 31e,
is put with the first gasket 80a, while, between the sloped walls,
21g and 31g, is set with the second gasket 80b. Although the second
gasket has a smaller diameter than that of the first gasket 80a,
the shielding function is not reduced because there is the double
structure of the sloped walls, 21g and 31g, and the outer wall 31d.
Because of the existence of the sloped side walls, 21g and 31g,
whose top surface smoothly continues from the front partition
walls, 21e and 31e, the second gasket 80b may be continuously
extended from the partition wall, 21e and 31e, to the saddle
portions, 20g and 30g.
FIG. 6 is a cross section of the transceiver 10 taken along the
longitudinal direction thereof. FIG. 6 explicitly illustrates the
first and second spaces, 10a and 10b, formed by the upper and lower
housings, 20 and 30, with the gasket 80a put between the front side
walls, 21e and 31e, and between the rear side walls, 21f and 31f.
Moreover, the second space 10b is also surrounded by the other
gasket 80b in the front side thereof to electrically shield the
second space 10b. Thus, the metal housings, 20 and 30, and two
gaskets, 80a and 80b, may effectively shield the first space 10a
for the electronic devices, and the second space 10b for the
optical components such as the ROSA 50 and the TOSA 60. Moreover,
between the IC 40a and the upper housing 20 is inserted with the
heat sinks 40b to conduct heat generated by the IC 40a to the cage
thorough the housing 20.
FIGS. 7 and 8 magnify the portion where the ROSA 50 and the TOSA 60
are electrically connected with the substrate 40. The present
transceiver 10 connects the OSAs, 50 and 60 with the substrate 40
by respective flexible printed circuits (hereafter denoted as FPC),
91 and 92. That is, the OSAs, 50 and 60, provide the device
portion, 50a and 60a, and the sleeve portion, 50b and 60b. The
device portion, 50a and 60a, extends a plurality of lead pins, 50c
and 60c. The FPC, 91 and 92, is soldered with the lead pin, 50c and
60c, in one end thereof; while, connected with the pads, 40i and
40j, on the substrate 40 in the other end. The FPC, 91 and 92, has
a shape that it is extended upward from the point connected with
the lead pin, bent downward at the hairpin portion, 91a and 92a,
and bent again with substantially right angle toward the rear of
the transceiver 10 to be connected with the pad, 40i and 40j, on
the substrate 40.
The transceiver 10 of the present embodiment provides a beam lead
devices, 95 and 96, on the substrate 40 to bend the FPCS, 91 and
92, at right angle. These lead devices, 95 and 96, are not
electrically connected with any circuit components at all. They are
prepared only to support to bend the FPCS, 91 and 92. That is, the
FPC boards, 91 and 92, whose end, 91e and 92e, is connected with
the pads, 40i and 40j, in the top surface of the substrate 40, is
bent upwardly at substantially right angle so as to be wound around
the outer surface of the lead device, 95 and 96, as being put
between the device, 95 and 96, and the substrate 40, folded back at
the hair pin portion, 91a and 92a, and is connected at the other
end thereof, 91c and 92c, with the lead pins, 50c and 60c,
extending from the device portion of the OSAs, 50a and 60a. The
lead devices, 95 and 96, used herein may be a type of rectifying
diode or a general purposed diode for a small signal application
whose diameter is about 1 mil or less. The optical transceiver 10
shown in the figures of the present application has the type of the
XFP transceiver whose height is determined by the MSA standard to
be 8.5 mm. In a case where the FPC board, 91 and 92, is bent within
such a small space, the curvature of the bend inevitably becomes
small, which causes a large stress on the connected portion with
the substrate 40, namely, the pad, 40i and 40j, soldered with the
FPC boards, 91 and 92. This may degrade the electrical reliability
of the soldered pad. The optical transceiver 10 of the present
embodiment, to relief the stress caused in the pad, 40i and 40j, on
the substrate 40, presses the FPC boards, 91 and 92 against the
substrate 40 with the lead devices, 95 and 96. Because the lead
devices, 95 and 96, are not electrically connected with anywhere,
this arrangement for the FPC boards, 91 and 92, does not cause any
influence on the electrical performance of the transceiver 10.
Next, a method to assemble the optical transceiver described above
will be explained. Firstly, the substrate 40 mounts the electronic
components including the ICs 40a thereon by the soldering to make
the electronic unit. Concurrently with and independent on the
assembly of this electronic unit, the semiconductor optical devices
such as a laser diode and a photodiode are assembled in the device
portions, 50a and 60a, and optically aligned with the sleeve
portions, 50b and 60b, to make the ROSA 50 and the TOSA 60,
respectively. The optical alignment of the device portion 50a with
the sleeve portion 50b thereof is carried out such that the
photodiode in the device portion 50a practically detects an optical
signal by a preset magnitude from the test fiber set within the
sleeve portion 50b. While, the alignment of the device portion 60a
with the sleeve portion 60b in the TOSA 60 is performed such that
the laser diode in the device portion 60b emits signal light to the
test fiber set in the sleeve portion 60b by being practically
provided with the driving current to the laser diode and the signal
light is detected from the other end of the testing fiber. Thus,
the ROSA 50 and the TOSA 60 are completed.
Secondly, the device portion of respective OSAs, 50a and 60a, are
assembled with the FPC boards, 91 and 92. The FPC boards, 91 and
92, provide in one end thereof a plurality of through-holes whose
positions correspond to the arrangement of the lead pins extending
from the device portion, 50a and 60a. Passing the lead pins into
these through-holes and soldering the lead pins with the land
around respective through-holes, the FPC boards, 91 and 92, are
assembled with respective OSAs, 50 and 60. Subsequently, the other
end of the FPC boards, 91e and 92e, are soldered with pads, 40i and
40j, on the substrate 40. Leveling the substrate 40, the sleeve
portion of respective OSA, 91c and 92c, heads their tip end
upward.
Next, the lead devices, 95 and 96, are set in positions closer to
the edge of the substrate 40 compared to the position where the FPC
boards is soldered with the pad, 40i and 40j, on the substrate 40.
In this process, the lead devices, 95 and 96, press the FPC boards,
91 and 92, against the substrate 40 such that, even when the ROSA
50 and the TOSA 60 are forced to bend the FPC boards, 91 and 92,
the pads in the edge of the FPC boards, 91e and 92e, may be free
from the stress. Subsequently, the FPC boards, 91 and 92, are bent
upward as tracing the outer surface of the lead devices, 95 and 96,
and folded back so as to form the hairpin portion, 91a and 92a, and
head the tip end of the sleeve portions of the ROSA 50 and the TOSA
60 forward.
Setting the substrate 40 with the ROSA 50 and the TOSA 60 in
respective positions 30g of the lower housing 30 and the gaskets,
80a and 80b, on top of the side walls of the lower housing 30, the
process puts the upper housing 20 on the lower housing 30. Fixing
the housings with the screws, the optical transceiver 10 according
to the present embodiment is completed. Here, where the side walls
of the lower housing 30 or the upper housing 20 provides the groove
in the top thereof and the gasket is set within the sleeve, the
assembly of the upper housing 20 with the lower housing 30 may be
facilitated.
While the preferred embodiments of the present invention have been
described in detail above, many changes to these embodiments may be
made without departing from the true scope and teachings of the
present invention. The present invention, therefore, is limited
only as claimed below and the equivalents thereof.
* * * * *